Handling and Surface Modificaiton pf Ultrafine Particles by CVD in Fluidized Bed Under Reduced Pressure

减压流化床中 CVD 处理和表面改性超细颗粒

• 批准号: 01850208
• 负责人: MOROOKA Shigeharu
• 金额: $ 1.28万
• 依托单位: Kyushu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B).
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01850208/
• 关键词: Fluidization ;; Ultrafine Particles ;; CVD ;; Ceramics ;; Surface Modification; 流動層; 気相合成; 超微粉体; プラズマ; 複合粒子; 減圧

Chemical vapor deposition method is very attractive to produce ultrafine particles with controlled chemical and crystalline compositions. One of the most important factors is how to handle fine particles in the gas phase. In this study, fluidization, which is normally used only for coarse particles, is refined for the handling of ultrafine particles.(1) Si_3N_4, SiC, Al_2O_3 and TiO_2 particles of 30-400 nm diameter were fluidized under 0.1-100 kPa and 25-200^ﾟC, and characteristics of bubbles, entrainment and mixing were evaluated by using optical fiber probes and pressure sensors equipped at various positions in the bed. The fluidization gas was dry air or nitrogen, and the gas velocity was larger than 1 cm/s. Cohesive particles were also fluidized by mixing coarse particles as the turbulent promoter. The fluidizability was correlated from the view of physicochemical properties of particles.(2) CVD processing were actually carried out in a bench-scale fluidized bed of 28 mm diameter. The coating of Si_3N_4 or Al_2O_3 with electro conductive TiN by the reaction of NH_3 and TiCl_4, and the coating of Al_2O_3 with thermo-conductive AIN by the reaction of NH_3 and AlCl_3 were among them. The results show that the fluidization is very effective to modify ultrafine particles by CVD reactions.

化学气相沉积法是制备化学成分和晶体成分可控的超细颗粒的有效方法。其中最重要的因素之一是如何处理气相中的细颗粒。在这项研究中，流化，通常只用于粗颗粒，细化处理超细颗粒。(1)在0.1 ~ 100 kPa、25 ~ 200^ cc的条件下，对直径为30 ~ 400 nm的Si_3N_4、SiC、Al_2O_3和TiO_2颗粒进行流态化，利用光纤探头和安装在床内不同位置的压力传感器，对气泡、夹带和混合特性进行了评价。流化气体为干燥空气或氮气，气速大于1 cm/s。黏结颗粒也通过混合粗颗粒作为湍流促进剂进行流化。从颗粒的物理化学性质出发，对流化性进行了关联。(2)在直径为28mm的实验床上实际进行了CVD处理。其中，NH_3与TiCl_4反应制备了Si_3N_4或Al_2O_3的导电TiN涂层，NH_3与AlCl_3反应制备了Al_2O_3的导热AIN涂层。结果表明，流态化对CVD修饰超细颗粒是非常有效的。

项目成果

H.Kawamura: "Plasma Surface Treatment of Milled Carbon Fiber in a Fluidized Bed Reactor" J.Materials Science Letters. (1991)

H.Kawamura：“流化床反应器中研磨碳纤维的等离子表面处理”J.Materials Science Letters。

H. Kawamura et al.: "Plasma Surface Treatment of Milled Carbon Fiber in a Fluidized Bed Reactor" J. Materials Science Letters.

H. Kawamura 等人：“流化床反应器中研磨碳纤维的等离子表面处理”J. 材料科学快报。

S. Morooka et al.: "Rate Analysis of Composite Ceramic Particles Production by CVD Reaction in a Fluidized Bed" AIChE Symposium Series.

S. Morooka 等人：“流化床中 CVD 反应生产复合陶瓷颗粒的速率分析”AIChE 研讨会系列。

S. Morooka et al.: "Fluidization of Fine Particles at Reduced Pressure" Powder Technology. Vol. 58. 125-130 (1989)

S. Morooka 等人：“减压细颗粒流化”粉末技术。

S.Morooka: "Fluidization of Fine Particles at Reduced Pressure" Powder Technology. 58. 125-130 (1989)

S.Morooka：“减压细颗粒流化”粉末技术。